Chapter 27 Acne
Acne can be treated both with topical and oral medications that may fall into either the prescription or over-the-counter (OTC) categories. Cosmeceuticals, of course, are OTC products that can alter some of the mechanics of acne formation. It is also possible that some cosmeceutical ingredients may even cause comedogenic acne. Substances that appear on the lists of comedogenic ingredients include cocoa butter, isopropyl myristate, industrial quality mineral oil, industrial quality petrolatum, and vegetable oils. No current cosmetic manufacturer would consider using anything but cosmetic grade mineral oil and petrolatum. Industrial grades are cheaper, but may also contain tar contaminants. These tar contaminants are comedogenic, possibly accounting for some of the older reports regarding the comedogenicity of mineral oil and petrolatum. However, these data are quite outdated and no longer pertinent to modern formulations. For all practical purposes, the concept of acne cosmetica is no longer germane.
The cosmeceuticals that are useful adjuvants in the treatment of acne are listed in Table 27.1. Salicylic acid, sometimes referred to as a beta hydroxy acid, is the mainstay of OTC acne treatments. It is an oil-soluble active able to penetrate into the sebum-rich milieu of the pore. Within the pore, it is able to loosen the comedonal plug and may exert some low level anti-inflammatory effects. It is a valuable ingredient for the treatment of acne and can be incorporated into cleansers, moisturizers, and facial foundations. Its ability to induce exfoliation has also allowed salicylic acid to function as an antiaging/acne ingredient for women with both needs. Glycolic acid, an alpha hydroxy acid, is used similarly; however, it is a water-soluble active that is not quite as potent a comedolytic. The last hydroxy acid acne cosmeceutical is lactobionic acid, a polyhydroxy acid that is used in the treatment of acne for patients with sensitive skin. It is not a potent comedolytic, but can function as a humectant, preventing barrier damage from acne medications.
Table 27.1 Cosmeceuticals for acne therapy
| Cosmeceutical | Effects on skin physiology | Patient selection comments |
| Salicylic acid | Exfoliation induced on the skin surface and in the follicular ostia, anti-inflammatory | Potent comedolytic suitable for sensitive skin |
| Glycolic acid | Exfoliation on the skin surface | Comedolytic best for photoaged skin |
| Lactobionic acid | Exfoliation on the skin surface with humectant and antioxidant effects, lower irritation profile | Moisturizing and comedolytic properties |
| Retinyl propionate | Possibly converted to biologically active retinoic acid in the skin, low irritation profile, stable | Mild retinoid effect suitable for sensitive skin |
| Retinol | Possibly converted to biologically active retinoic acid in the skin, more irritation possible, less stable | Mild retinoid effect suitable for photoaged skin |
| Niacinamide | Enhanced exfoliation without low pH due to NADPH pathway | Oil reduction and exfoliation effects combined, appropriate for sensitive skin |
| Zinc | Anti-inflammatory | May be used both orally and topically as antiacne treatment |
The OTC retinoids are gaining popularity for the treatment of acne, in addition to photoaging. Small amounts of both retinyl propionate and retinol may be converted to tretinoin in the dermis. Tretinoin is an established prescription active for the treatment of acne through the elimination and prevention of microcomedones. The enzymatic machinery that transforms the OTC retinoids into prescription retinoids is the rate-limiting factor. Nevertheless, the daytime wear of stable retinoids in the form of moisturizers may be helpful in acne patients.
Several ingredients have been touted for acne that are not listed inm Table 27.1. One ingredient is triclosan, an antibacterial found in surgical hand scrubs, antibacterial soaps, deodorant soaps, and rinseless hand antiseptics. While triclosan is found in several cosmeceutical acne treatment lines, it is not very effective at reducing the Propionibacterium acnes counts and is not listed for this reason. There are a variety of botanicals that have been touted for their acne effect, which is primarily antiinflammatory in nature. These ingredients are better at reducing facial redness and are discussed in Chapter 23 for this reason.
